That's just crazy talk. If it's more dangerous than a car I'll eat my hat.
According to NYT/Flightaware, there were ~8600 737Max flights per week. Let's call it 8000, and limit our analysis to the past year. Let's also make the very low assumption there are only 100 passengers on each.
8000 * 100 * 50 is very conservative 40 million passenger trips per year. And there were 350 deaths.
Cars have a fatality rate of ~1 per 100 million miles. That means that the average distance traveled needs to be ~1000 miles to be better than cars.
I challenge you to find better numbers estimates, but my very conservative numbers says they're on par or better than cars. I must confess I'm a little surprised how close it was.